The photographic process, in which silver halides are used is conventionally most widely used, since it is excellent in photographic characteristics, such as sensitivity and gradation adjustment, in comparison with another photographic process such as, for example, electrophotography and diazo photography. It is still vigorously investigated because the highest image quality as, in particular, color hard copies can be obtained.
In recent years, from the image-formation processing method of light-sensitive materials in which silver halides are used, a system that can give an image simply and quickly by using, for example, an instant photographic system having a built-in developing solution or a dry-process heat development processing using heating or the like, has been developed in place of the conventional wet process. As heat development color light-sensitive materials, products called PICTROGRAPHY and PICTROSTAT (trade names) have been marketed by Fuji Photo Film Co., Ltd. This simple, quick processing method uses a redox compound having a preformed dye linked (hereinafter referred to as a coloring material), to carry out the color image formation. On the other hand, as the method for the color image formation for photographic light-sensitive materials, one in which a coupling reaction of a coupler with the oxidized product of a developing agent is used, is most popular. Heat development color light-sensitive materials that employ that method are disclosed, for example, in U.S. Pat. Nos. 3,761, 270, 4,021,240 and JP-A-59-231539 ("JP-A" means unexamined published Japanese patent application) and JP-A-60-128438, wherein p-sulfonamidophenol is used as a developing agent. Since, in the light-sensitive materials that employ a coupling system, the couplers do not have absorption in the visible region before they are processed, the light-sensitive materials that employ a coupling system are advantageous over light-sensitive materials that use a coloring material in view of sensitivity. Further, it is considered that the light-sensitive materials that employ a coupling system have the advantage that they can be used not only as printing materials but also as photographing (shooting) materials.